Silent gear and method of making the same



' 1,638,255 Aug 9 1927 J. R. GAMMETER SILENT'GEAR AND METHOD OF MAKING THE SAME Filed Nov. SQ 1924 Patented ug. 9, 1927.

UNITED STATES PATENT OFFICE.

JOHN R. GAMMETER, OF AKRON, OHIO, ASSIG'NOR TOTHE B. F. GOODRICH COMPANY, e OF NEW YORK. N. Y., A CORPORATION 0F NEW YORK.

SILENT GEAR AND METHOD OF MAKING THE SAME.

Application led November 8, 1924. Serial No. 748,577.

This invention relates to noiseless or nonresonant gears having teeth and adjacent portions made of fabric and a binder and has for an object to provide a gear of this character which' shall be economical to manufacture and uniformly strong throughout its periphery. A further object is to provide a method of making such gears with minimum waste of material and expenditure of labor.

Of the accompanying drawings, Fig. 1 is a view inside elevation of a gear illustrating a preferred embodiment of my invention and Fig. 2 is a perspective view of the helically woven fabric tape employed in the production of the outer toothed annulus.

It has heretofore been proposed to construct gear blanks of a plurality of layers of fabric superimposed on one another and bound together to form an integral structure by the impregnation with and the subsequent hardening of asuitable binding material. These prior constructions of fabric gears have, so far as I am aware,- involved the laying up of woven fabric in stacks and cutting an annulus therefrom, or the cutting of short segments of the annulus, the chords of the segments aligning with the threads of the fabric, and building up the annulus by hand by superimposing the segments upon each other in overlapped relation. Both of thee methods are wasteful of the fabric, the

latter particularly is laborious, and the final product lacks capacity to resist uniformly in all directions abrasion and the torsional stresses imposed thereon.

In accordance with the present invention, I employ a metal wheel and secure to its periphery a relativelynarrow tooth-forming annulus consisting of a requisite number of convolutions of a continuous fabric strip or tape wound edgewise, or several strips thus wound, each of sufficient length to make one or more complete convolutions. To provide uniform strength and resistance to wear in the teeth, I prefer to utilize a special, arcuately-woven fabric tape having a normal curvature substantially the same as it is to assume in the convoluted annulus. The convolutions of this tape being positioned edgewise to the periphery of the wheel, the warp threads of the fabric lie circumferentially and the weft threads radially of the gear, giving to the fabric structure not only material, such as metal, wood, or fiber composition, and preferably has a central opening y12 for the gear shaft and a peripheral surface or rim 13 for the engagement of the tooth-forming portion 11. This rim is roughened by providing it with numerous transverse, shallow notches or grooves 13" for interlocking engagement with said portion 11. The portion 11 is formed of a fabric tape 14, impregnated or coated with a suitable hardening `binder such as rubber, Celluloid or phenolic condensation product of the class of bakelite, and wound edgewise onto the periphery of the wheel 10, as on the rim 13. the convolutions being laterally pressed together as the winding proceeds. When a requisite thickness of fabric has been plied up, the fabric annulus is subjected to heavy transverse compression,` both to cause it to hug the wheel portion 10 and to consolidate the layers with each other, the pressure being preferably maintained during the hardening of the impregnating material. The result is a substantially rigid gear blank having a tooth-forming portion of hardened binder and fabric of the described character. The teeth 15 are then formed in the annulus 11 by means of any suitable gear-cutting machine.

The fabric tape 14, in this preferred embodiment, is of a special arcuate weave, illustrated in Fig. 2, in which the warp threads 16 are of increasingly greater length from the inner edge 17 to the outer edge 18 of the tape. This is normally effected in the weaving by causing a graduated increase in speed of the warp 'threads from the inner selvage 17 to the outer selvage 18, the weftthreads 19 being as a consequence more widely spaced at the outer edge of tape. As the fabric is delivered from the loom, it assumes a coiled form, the helical convolutions lying smoothly with their flat sides 20 adjacent, the warp threads 16 running circumferentially and the weft threads 19 radially of the convoluted l fabric. VI desired, the weft threads may bey Inits an even tension'tobe giventhe' threads i oi the fabric and" enables the several plies to be wound with smooth contacting surfaces.

The' plies of fabric, may be impregnated' 'bejy -oreivinding to orin the annulus, eachjply' being pressed in place as it is applied, or the'.

tape may p he lconvoluted and then impregj nated, as by dipping. Ineither case, the con-` voluted fabricis subjected to transverse con` pression and the vyimpregnating substance solidii'ed, as, [where bakelite or V-ulcanizableiribbei'are e1nployedhy the application of heaty n Th-ille I have lshown butfone form, oit v gear en'ibodyinginy invention andy While I have referredinthe 'speciiCatQll to, forming the 'fabric annulus directly` uponl the central wheel portionof the gear, itis obviousthat numerous variations and modifications in the construction of the gear may be made without departing from the principles of this invention, and that the tooth-forming annulus may be niad'e in other ways, as, for example, separate from and detachable with re-` spect to the centraluvheel; portion of thegear. Itherelore donot purposeto limit the claims of this application otherwise than as necessitated by the pi-ior art# I claim:

l". rPhe inetliodof making agear which coinprises Weaving-in helical forni. a unitary strip of tliread-coinprising sheet materialfwithlthe strip radially disposed in the heligvforming an. annulus of the strip by; securing suecessive 'turns thercof'together with a bondinginaterial, andf'forming gearl t'eetl'i'.` on the annulus.`y 4 i A ojear comprising ahel'ically Woven strip ot thread-comprising material, the strip being radially disposed in the helix,y and bonding nieans securing successive turns ofthe strip togetherin the forrnoof an annulus, the threadsin eachl tooth of the gear having thesanie dispositionwnvith relation to the tooth.v j K 3. A gear as deined in claiinf 2` in Whielfivr one set, of threads` is disposedk radially and another the gear.

hand this 6th day of.eNovem'ber,` 1924i.

In Witness whereof' I have hereunto, setiny.

2 rJoni-i ai-GAMMETER; :ifl

enY

lset is disposed circlilnfverentially` of 

